Complete saponification and acidulation of natural oil processing byproducts and treatment of reaction products

ABSTRACT

The present invention generally provides a process for treating a soapstock. The present invention more particularly provides systems and methods for treating a soapstock to generate free fatty acids and/or fatty acid derivatives, e.g. fatty acid alkyl esters. The present invention more particularly provides systems and methods for realizing the full fatty acid yield of a soapstock by first converting substantially all of the saponifiable material in a soapstock to salts of fatty acids (soaps) and acidulating the soaps to generate free fatty acids and/or fatty acid derivatives, e.g. fatty acid alkyl esters, wherein the soapstock comprises soaps and saponifiable lipids, e.g. glycerides and/or phospholipids, and the generating of free fatty acids and/or fatty acid is achieved without the use of a mineral acid.

FIELD OF THE INVENTION

The present invention generally provides a process for treating asoapstock. The present invention more particularly provides systems andmethods for treating a soapstock to generate free fatty acids and/orfatty acid derivatives, e.g. fatty acid alkyl esters. The presentinvention more particularly provides systems and methods for realizingthe full fatty acid yield of a soapstock by first convertingsubstantially all of the saponifiable material in a soapstock to saltsof fatty acids (soaps) and acidulating the soaps to generate free fattyacids and/or fatty acid derivatives, e.g. fatty acid alkyl esters,wherein the soapstock comprises soaps, saponifiable lipids, e.g.glycerides and/or phospholipids, and the generating of free fatty acidsand/or fatty acid is achieved without the use of a mineral acid.

BACKGROUND OF THE INVENTION

Crude (unrefined) Animal and vegetable oils (referred to hereincollectively as “natural oils”) are typically subjected to a variety ofprocessing steps to remove specific undesirable components of the crudeoil prior to sale. The type, number, and sequencing of processing stepscan vary depending on the crude oil feedstock, refinery type (e.g.physical vs. alkaline) and configuration, target product markets, andthe like. In general, crude natural oils are refined to remove excessquantities of “gums” (comprised primarily of phospholipids), free fattyacids, as well as various coloring components and volatile compounds.

Once removed from the crude oil, the refining byproducts are either solddirectly into low-value markets such as animal feed, or furtherprocessed into higher-value products. Two major byproducts of thechemical refining processes of natural oils are soapstock and gums. Inmost natural oil refineries utilizing the chemical refining process,phosphoric acid or an equivalent acid is added to the crude oil toincrease the solubility of the phospholipids (gums) in water. Next, astrong base, typically sodium hydroxide (NaOH) is added, reacting withthe free fatty acids in the oil to form soaps (salts of free fattyacids). Water is then added to the oil to remove the soaps andsolubilized gums. Soapstock is typically acidulated to generate freefatty acids. Gums are typically sold into low-value animal feed marketsor upgraded to food-grade emulsifiers, e.g. lecithin.

In most chemical refining configurations, additional waste streams aregenerated which represent low- or negative-value byproducts. Forexample, it typically necessary to perform an additional water wash onthe oil after the majority of the gums and soaps have been removed. Thelipid content of this washwater (referred to as Soapstock Makeup) cancontain from about 5% to about 20% soaps and other lipids, but the lipidcontent is generally not sufficiently high to justify the costs offurther processing into value added products. In addition, all of theabove referenced byproduct streams from the chemical refining processcontain various amounts of saponifiable material that are not convertedto free fatty acids.

Nothing in the prior art pros ides the benefits attendant with thepresent invention.

Therefore, it is an object of the present invention to provide animprovement which overcomes the inadequacies of the prior art methodsand devices and which is a significant contribution to the advancementto realizing the full fatty acid yield of saponifiable material.

Another object of the present invention is to provide a method forgenerating free fatty acids from a mixed lipid feedstock, the methodcomprising: providing the mixed lipid feedstock; combining the mixedlipid feedstock with a base to form a mixture; allowing the mixture toreact in a reaction vessel; introducing carbon dioxide into the reactedmixture in the reaction vessel to form a first carbonic acid within thereaction vessel; mixing the first carbonic acid and the reacted mixturewithin the reaction vessel; allowing the first carbonic acid and reactedmixture to settle within the reaction vessel; and draining a firstaqueous layer from the reaction vessel.

Yet another object of the present invention is to provide a method forgenerating free fatty acids from a mixed lipid feedstock, the methodcomprising: providing the mixed lipid feedstock; combining the mixedlipid feedstock with a base to form a mixture; allowing the mixture toreact in a reaction vessel; introducing carbon dioxide into the reactedmixture in the reaction vessel to form a first carbonic acid within thereaction vessel; mixing the first carbonic acid and the reacted mixturewithin the reaction vessel; allowing the first carbonic acid and reactedmixture to settle within the reaction vessel; draining a first aqueouslayer from the reaction vessel; collecting the first aqueous layer; andtreating the collected first aqueous layer with calcium oxides,magnesium oxides, barium oxides, or other polyvalent oxides.

Still yet another object of the present invention is to provide a methodfor generating free fatty acids from a mixed lipid feedstock, the methodcomprising; providing the mixed lipid feedstock; combining the mixedlipid feedstock with a base to form a first mixture; allowing the firstmixture to react in a reaction vessel; combining the reacted firstmixture with an organic or inorganic acid, thereby acidulating soaps inthe first mixture to generate free fatty acids; draining a first aqueouslayer from the reaction vessel; combining the generated free fatty acidswith an alcohol to form a second mixture; and heating and pressurizingthe second mixture to above the critical temperature and pressure of thealcohol, thereby esterifying substantially all of the free fatty acidsto generate fatty acid alkyl esters.

Another object of the present invention is to provide a method forgenerating free fatty acids from a mixed lipid feedstock, the methodcomprising: a) providing the mixed lipid feedstock; b) combining themixed lipid feedstock with a base to form a first mixture; c) allowingthe first mixture to react in a reaction vessel; d) introducing carbondioxide into the reacted mixture in the reaction vessel to form a firstcarbonic acid within the reaction vessel; e) mixing the first carbonicacid and the reacted mixture within the reaction vessel; f) allowing thefirst carbonic acid and reacted mixture to settle within the reactionvessel; g) draining a first aqueous layer from the reaction vessel; h)removing a generated lipid layer from the reaction vessel; and i)repeating steps a) through h) above up to 8 times using the generatedlipid layer from the reaction vessel as the mixed lipid feedstock forstep a).

Yet another object of the present invention is to provide a method forgenerating an animal feed additive from a mixed lipid feedstock, themethod comprising: providing the mixed lipid feedstock; combining themixed lipid feedstock with a base to form a mixture; allowing themixture to react in a reaction vessel; introducing carbon dioxide intothe reacted mixture in the reaction vessel to form a first carbonic acidwithin the reaction vessel; mixing the first carbonic acid and thereacted mixture within the reaction vessel; allowing the first carbonicacid and reacted mixture to settle within the reaction vessel; draininga first aqueous layer from the reaction vessel; and concentrating thefirst aqueous layer to generate a sodium bicarbonate product that issubstantially free of any water.

The foregoing has outlined some of the pertinent objects of the presentinvention. These objects should be construed to be merely illustrativeof some of the more prominent features and applications of the intendedinvention. Many other beneficial results can be attained by applying thedisclosed invention in a different manner or modifying the inventionwithin the scope of the disclosure. Accordingly, other objects and afuller understanding of the invention may be had by referring to thesummary of the invention and the detailed description of the preferredembodiment in addition to the scope of the invention defined by theclaims taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention provides a process for treating a soapstock. Thepresent invention more particularly provides systems and methods fortreating a soapstock to generate free fatty acids and/or fatty acidderivatives, e.g. fatty acid alkyl esters. The present invention moreparticularly provides systems and methods for realizing the full fattyacid yield of a soapstock by first converting substantially all of thesaponifiable material in a soapstock to salts of fatty acids (soaps) andacidulating the soaps to generate free fatty acids and/or fatty acidderivatives, e.g. fatty acid alkyl esters, wherein the soapstockcomprises soaps and saponifiable lipids, e.g. glycerides and/orphospholipids, and the generating of free fatty acids and/or fatty acidis achieved without the use of a mineral acid.

A feature of the present invention is to provide a method for generatingfree fatty acids from a mixed lipid feedstock. The method comprising thefollowing steps as described herein. The mixed lipid feedstock isprovided. The mixed lipid feedstock is combined with a base to form afirst mixture. The first mixture is allowed to react. Carbon dioxide isintroduced into the reacted mixture in the reaction vessel to form afirst carbonic acid within the reaction vessel. The first carbonic acidis mixed with the reacted mixture within the reaction vessel. The firstcarbonic acid and reacted mixture are allowed to settle within thereaction vessel. A first aqueous layer is drained from the reactionvessel, thereby acidulating soaps in the first mixture to generate freefatty acids. The method can further comprise the following steps asdescribed herein. The first aqueous layer can be filtered using a sizeexclusion filtration system. The filtering step can further comprise afilter having a membrane having a plurality of pores wherein the poresallow soaps and phosphates to pass through the membrane of the filter.The filtering step can further comprise a filter having a membranewherein the membrane allows particles having a molecular weight lessthan the molecular weight of a salt to pass through the filter. Thefiltering step can further comprise maintaining a pH of the firstaqueous layer between about 6 and 11. The filtering step can furthercomprise maintaining a pressure of the first aqueous layer between about50 and 800 psi. The filtering step can further comprise maintaining atemperature of the first aqueous layer between about 23 and 100° C. Themethod can further comprise an electrolysis step wherein a lipid phasecomprising a small amount of unreacted soaps is transferred to anelectrolysis unit wherein the unreacted soaps in the lipid phase arereacted with an anolyte to generate free fatty acids. The method canfurther comprise concentrating the first aqueous layer from each step.The concentration step can further comprise maintaining a pH of thefirst aqueous layer between about 6 and 11. The concentration step canfurther comprise maintaining a pressure of the first aqueous layerbetween about 0 and 800 psi. The concentration step can further comprisemaintaining a temperature of the first aqueous layer between about 23and 100° C. The method can further comprise combining generated freefatty acids with an alcohol to form a second mixture; and heating andpressurizing the second mixture to above the critical temperature andpressure of the alcohol, thereby esterifying substantially all of thefree fatty acids to generate fatty acid alkyl esters. The method canfurther comprise combining generated free fatty acids with an alcohol toform a second mixture; and reacting the second mixture to form a fattyalkyl ester. The method can further comprise using a catalyst to causethe reaction of the mixed lipid feedstock with the base. The catalystcan be an acid catalyst. The method can further comprise removinggenerated free fatty acids from neutral lipids; and reacting the neutrallipids to form a fatty alkyl ester. The method can further compriseusing a catalyst to cause the reaction of the neutral lipids. Thecatalyst can be a base catalyst. The method can further comprise anelectrolysis step wherein a lipid phase comprising a small amount ofunreacted soaps is transferred to an electrolysis unit wherein theunreacted soaps in the lipid phase are reacted with an anolyte togenerate free fatty acids. The carbon dioxide can be introduced as agaseous flow of carbon dioxide into the reaction vessel. The carbondioxide can be introduced as a gaseous flow of carbon dioxide into waterand wherein the water is introduced to the reaction vessel. Thegenerated free fatty acids can be separated, isolated, or purified intoseparate fractions. The mixed lipid feedstock can be selected from thegroup consisting of a soapstock, a washwater comprising soaps, and acombination thereof as generated during the chemical refining of a crudenatural oil. The mixed lipid feedstock can be a tall oil soapstock. Thecrude natural oil can be a vegetable oil. The vegetable oil can beselected from the group consisting of soybean oil, canola oil, rapeseedoil, corn oil, rice oil, sunflower oil, peanut oil, sesame oil, palmoil, algae oil, jatropha oil, castor oil, safflower oil, grape seed oil,and any combination of vegetable oils. The mixed lipid feedstock canfurther comprise: water, soaps, phospholipids, saponifiable material,and unsaponifiable material. The organic acid can be carbonic acid. Thecarbonic acid can be generated by adding carbon dioxide to thesaponification product mixture, thereby causing the carbon dioxide toreact with the water in the saponification product mixture to formcarbonic acid.

Another feature of the present invention is to provide a method forgenerating free fatty acids from a mixed lipid feedstock. The methodcomprising the following steps as described herein. The mixed lipidfeedstock is provided. The mixed lipid feedstock is combined with a baseto form a mixture. The mixture is allowed to react in a reaction vessel.Carbon dioxide is introduced into the reacted mixture in the reactionvessel to form a first carbonic acid within the reaction vessel. Thefirst carbonic acid is mixed with the reacted mixture within thereaction vessel. The first carbonic acid and reacted mixture is allowedto settle within the reaction vessel. A first aqueous layer is drainedfrom the reaction vessel. The collected first aqueous layer is treatedwith calcium oxides, magnesium oxides, barium oxides, or otherpolyvalent oxides. The method can further comprise the following stepsas described herein. The treated collected first aqueous layer can beoxidized. The method can further comprise an electrolysis step wherein alipid phase comprising a small amount of unreacted soaps is transferredto an electrolysis unit wherein the unreacted soaps in the lipid phaseare reacted with an anolyte to generate free fatty acids.

Yet another feature of the present invention is to provide a method forgenerating free fatty acids from a mixed lipid feedstock. The methodcomprising the following steps as described herein. The mixed lipidfeedstock is provided. The mixed lipid feedstock is combined with a baseto form a mixture. The mixture is allowed to react in a reaction vessel.The reacted first mixture is combined with an organic or inorganic acid,thereby acidulating soaps in the first mixture to generate free fattyacids. The generated free fatty acids are combined with an alcohol toform a second mixture. The second mixture is heated and pressurized toabove the critical temperature and pressure of the alcohol, therebyesterifying substantially all of the free fatty acids to generate fattyacid alkyl esters. The method can further comprise the following stepsas described herein. The method can further comprise an electrolysisstep wherein a lipid phase comprising a small amount of unreacted soapsis transferred to an electrolysis unit wherein the unreacted soaps inthe lipid phase are reacted with an anolyte to generate free fattyacids. The organic acid can be a carbonic acid. The carbonic acid can begenerated by adding carbon dioxide to the saponification productmixture, thereby causing the carbon dioxide to react with the water inthe saponification product mixture to form a first carbonic acid. Thecarbon dioxide can be introduced as a gaseous flow of carbon dioxideinto the reaction vessel. Carbon dioxide can be introduced into thereacted mixture in the reaction vessel to form a second carbonic acidwithin the reaction vessel. The second carbonic acid can be mixed withthe reacted mixture within the reaction vessel. The second carbonic acidand reacted mixture can be allowed to settle within the reaction vessel.A second aqueous layer can be drained from the reaction vessel. Carbondioxide can be introduced into the reacted mixture in the reactionvessel to form a third carbonic acid within the reaction vessel. Thethird carbonic acid can be mixed with the reacted mixture within thereaction vessel. The third carbonic acid and reacted mixture can beallowed to settle within the reaction vessel. A third aqueous layer canbe drained from the reaction vessel. Hexane can be added to the reactedmixture in the reaction vessel after the draining of the third aqueouslayer. Carbon dioxide can be introduced into the reacted mixture in thereaction vessel to form a fourth carbonic acid within the reactionvessel. The fourth carbonic acid can be mixed with the reacted mixturewithin the reaction vessel. The fourth carbonic acid and reacted mixturecan be allowed to settle within the reaction vessel. A fourth aqueouslayer can be drained from the reaction vessel.

Still yet another feature of the present invention is to provide amethod for generating free fatty acids from a castor oil. The methodcomprising the following steps as described herein. The castor oil isprovided. The castor oil is combined with a base to form a mixture. Themixture is allowed to react in a reaction vessel. Carbon dioxide isintroduced into the reacted mixture in the reaction vessel to form afirst carbonic acid within the reaction vessel. The first carbonic acidand the reacted mixture are mixed within the reaction vessel. The firstcarbonic acid and reacted mixture is allowed to settle within thereaction vessel. A first aqueous layer is drained from the reactionvessel. The method can further comprise the following steps as describedherein. The carbon dioxide can be introduced as a gaseous flow of carbondioxide into the reaction vessel. Carbon dioxide can be introduced intothe reacted mixture in the reaction vessel to form a second carbonicacid within the reaction vessel. The second carbonic acid can be mixedwith the reacted mixture within the reaction vessel. The second carbonicacid and reacted mixture can be allowed to settle within the reactionvessel. A second aqueous layer can be drained from the reaction vessel.Carbon dioxide can be introduced into the reacted mixture in thereaction vessel to form a third carbonic acid within the reactionvessel. The third carbonic acid can be mixed with the reacted mixturewithin the reaction vessel. The third carbonic acid and reacted mixturecan be allowed to settle within the reaction vessel. A third aqueouslayer can be drained from the reaction vessel. Hexane can be added tothe reacted mixture in the reaction vessel after the draining of thethird aqueous layer. Carbon dioxide can be introduced into the reactedmixture in the reaction vessel to form a fourth carbonic acid within thereaction vessel. The fourth carbonic acid can be mixed with the reactedmixture within the reaction vessel. The fourth carbonic acid and reactedmixture can be allowed to settle within the reaction vessel. A fourthaqueous layer can be drained from the reaction vessel.

Another feature of the present invention is to provide a method forgenerating free fatty acids from a mixed lipid feedstock. The methodcomprising the following steps as described herein. The mixed lipidfeedstock is provided as step a). The mixed lipid feedstock is combinedwith a base to form a mixture as step b). The mixture is allowed toreact in a reaction vessel as step c). Carbon dioxide is introduced intothe reacted mixture in the reaction vessel to form a first carbonic acidwithin the reaction vessel as step d). The first carbonic acid is mixedwith the reacted mixture within the reaction vessel as step e). Thefirst carbonic acid and reacted mixture is allowed to settle within thereaction vessel as step f) A first aqueous layer is drained from thereaction vessel as step g). A generated lipid layer is removed from thereaction vessel as step h). Steps a) through h) are repeated above up to8 times using the generated lipid layer from the reaction vessel as themixed lipid feedstock for step a). The method can further compriseadding a salt to the generated lipid layer prior to any of thereactions. The salt can be sodium chloride. The method can furthercomprise adding sodium bisulfate to the generated lipid layer producedin any of the one or more reactions.

Yet another feature of the present invention is to provide a method forgenerating an animal feed additive from a mixed lipid feedstock. Themethod comprising the following steps as described herein. The mixedlipid feedstock is provided. The mixed lipid feedstock is combined witha base to form a first mixture. The first mixture is allowed to react.Carbon dioxide is introduced into the reacted mixture in the reactionvessel to form a first carbonic acid within the reaction vessel. Thefirst carbonic acid is mixed with the reacted mixture within thereaction vessel. The first carbonic acid and reacted mixture are allowedto settle within the reaction vessel. A first aqueous layer is drainedfrom the reaction vessel. The first aqueous layer is concentrated togenerate a sodium bicarbonate product that is substantially free of anywater, thereby generating an animal feed additive. The concentrationstep can further comprise using evaporation, fluidized bed drying,rotary drum drying, lyophilization, spray drying and reverse osmosis.

The foregoing has outlined rather broadly the more pertinent andimportant features of the present invention in order that the detaileddescription of the invention that follows may be better understood sothat the present contribution to the art can be more fully appreciated.Additional features of the invention will be described hereinafter whichform the subject of the claims of the invention. It should beappreciated by those skilled in the art that the conception and thespecific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is allow diagram of an exemplary method of the inventioncomprising generating free fatty acids and, optionally, fatty acid alkylesters from a mixed lipid feedstock comprising soaps, saponifiablematerial or equivalents thereof.

Reference will now be made in detail to various exemplary embodiments ofthe invention. The following detailed description is provided to givethe reader a better understanding of certain details of aspects andembodiments of the invention, and should not be interpreted as alimitation on the scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In alternative embodiments, the invention provides processes for thepreparation of fatty acids and optionally fatty acid derivatives, e.g.fatty acid alkyl esters, from mixed lipid feedstocks comprisingsaponifiable material, including byproduct streams of natural oilprocessing e.g. soapstocks, gums, or mixtures thereof. In alternativeembodiments, the feedstock comprises soapstock obtained from thealkaline neutralization of a crude natural oil. In alternativeembodiments, the feedstock comprises the gums product (comprisingprimarily phospholipids) generated during the degumming of a naturaloil. In alternative embodiments, the feedstock comprises a mixture ofproduct streams generated during the processing of crude natural oil andcomprises soaps as well as saponifiable lipids, e.g. phospholipidsglycerides, e.g. mono-, di-, and/or triglycerides, or any combinationthereof. In alternative embodiments, processes of the invention are moreeconomical and efficient than currently used approaches for thetreatment of natural oil processing byproducts e.g. soapstocks and gums,to generate fatty acids, fatty acid derivatives, or other value-addedproducts.

In alternative embodiments, a mixed lipid feedstock, e.g. a soapstockcomprising soaps as well as saponifiable material (e.g. glyceridesand/or phospholipids) is reacted with a base in a first saponificationstep to convert the saponifiable material to soaps (salts of fattyacids), thereby generating a product in which substantially all of thesaponifiable material is consorted to soaps. The soaps present in theproduct stream generated in the foregoing saponification step are thenseparated and reacted with an acid in a second acidulation step of theprocess in which substantially all of the soaps are acidulated to formfree fatty acids (i.e. fatty acids with no ester moiety) and a salt,e.g. sodium bicarbonate if sodium hydroxide is the selected base used inthe saponification step. Optionally, the free fatty acids are reactedwith a supercritical alcohol in a third step of the process to generatefatty acid alkyl esters.

Crude (unrefined) natural oils, including plant- and animal-derivedoils, are comprised primarily of triacylglycerols (i.e. triglycerides),as well as smaller portions of various lipids including mono- anddiacyleglycerols, (i.e. mono-glycerides and di-glycerides,respectively), free fatty acids, phospholipids, waxes, and othernon-lipid components including, for example, ketones, aldehydes, andhydrocarbons. Prior to sale for human consumption or for furtherprocessing, a crude natural oil is usually refined to remove themajority of the non-triglyceride components. The majority of naturaloils are refined using the chemical refining process. In the first stageof the chemical refining process, referred to as “degumming”, crude oilsare first washed with water to remove the hydratable phospholipids(gums). The resulting product stream separated from the oil during thedegumming step is referred to as “gums.” Second, the degummed oils aresubjected to a neutralization step in which the degummed oil is treatedwith a strong base, e.g. sodium hydroxide. During the neutralizationstep, free fatty acids present in the oil react with the base to formsoaps (salts of fatty acids). In some refineries, there is an additionalprocessing step between the degumming and neutralization step in which asmall amount of a mineral acid, e.g. phosphoric acid or citric acid) isadded to the degummed oil to convert any non-hydratable phospholipidsinto hydrated phospholipids. After the neutralization step, the oil iswashed to remove the soaps and, if the oil was treated with a mineralacid, the hydrated phospholipids. The resulting product stream separatedfrom the oil during the neutralization step is referred to as“soapstock.” If the oil is to be sold for human consumption, thedegummed, neutralized oil is then subjected to further processingincluding, e.g. bleaching and deodorization steps.

Depending on the configuration of the refinery, soapstock and gums areeither stored separately or combined into a single storage container.When referred to herein, a “mixed lipid feedstock” refers to anymaterial or composition comprising soaps as well saponifiable material,i.e. lipids capable of reacting to produce soaps (salts of fatty acids).Saponifiable material in the mixed lipid feedstock can include, withoutlimitation, glycerides, e.g. mono-glycerides, di-glycerides, ortriglycerides, or a combination thereof, and/or phospholipids. Inalternative embodiments, the mixed lipid feedstock is a soapstock. Inalternative embodiments, the mixed lipid feedstock comprises soaps andsaponifiable lipids e.g. glycerides and/or phospholipids. In alternativeembodiments, the mixed lipid feedstock is a mixture of soapstocks,comprising soaps, saponifiable material, e.g. glycerides and/orphospholipids, obtained during the processing of a natural oil. Inalternative embodiments, the mixed lipid feedstock is a soapstockwashwater obtained from the processing of a crude natural oil followingthe neutralization step in the chemical refining process. In suchembodiments, the washwater can comprise water and soapstock, wherein thesoapstock comprises soaps, glycerides, phospholipids, free fatty acids,and unsaponifiable material e.g. waxes and/or sterols. In alternativeembodiments, the soapstock washwater can comprise between about 1%soapstock to about 90% soapstock, e.g. between about 2% and 80%soapstock, about 3% and 70% soapstock, about 4% and about 60% soapstock.about 5% and about 50% soapstock, about 6% and about 40% soapstock,about 7% and about 30% soapstock, about 8% and about 20% soapstock,about 9% and about 15% soapstock, or between about 20% and about 12%soapstock, the remaining portion of the soapstock washwater comprisingwater. The composition of the soapstock used as a mixed lipid feedstockin accordance with the present invention can vary depending on the crudenatural oil from which it was derived. Table 1 shows the composition ofvarious soapstocks described in U.S. Pat. No. 4,118,407.

TABLE 1 Composition of soapstocks from the refining of various naturaloils Composition Soybean Cottonseed Coconut Palm Kernel Palm Water 57.358.6 66.8 57.8 66.4 Neutral Oil 14.6 13.0 17.4 26.2 8.4 FFA 1.46 0.940.55 0.24 1.25 Unsaponifiable 1.1 1.4 0.85 0.38 0.2 Soap 14.2 17.5 14.414.2 23.8 Phosphatide 11.34 8.56 0 0 0 Phosphorus 0.8 0.38 0.16 0 0Total FFA 23.7 27.6 27.3 38.1 21.9 pH 9.5 9.5 9.2 9.2 10.8

Other mixed lipid feedstocks suitable for use in the present processinclude tall oil soaps. Tall oil soaps are generated via the alkalinepulping of wood in the Kraft process. The alkaline pulping of wood usingthe Kraft process results in the production of black liquor, comprisingthe majority of the non-cellulose components of the wood. These productsinclude hemicelluloses, lignin, and various salts of carboxylic acidsincluding rosin salts and soaps (salts of fatty acids). After the blackliquor is concentrated using multiple effect evaporators, it is allowedto settle or is centrifuged. As the concentrated black liquor settles,the soaps float to the surface where they are skimmed and removed. Theskimmed product (referred to as black liquor soaps or tall oil soaps) isused as a feedstock in various embodiments of the process.

In alternative embodiments, the mixed lipid feedstock in the presentprocess is a saponified crude natural oil, e.g. a saponified vegetableoil. In alternative embodiments, the mixed lipid feed feedstock is asaponified castor oil, i.e. a composition comprising soaps derived frommixing a base with a castor oil, the saponifiable content in the castoroil, e.g. glycerides, and phospholipids, having been converted to soaps.It is known in that the majority of the fatty acid content in castor oil(e.g. between 80 to about 95% of the fatty acid content) is ricinoleicacid (12-hydroxy-9-cis-octadecenoic acid). In alternative embodiments,the invention provides methods or processes for generating ricinoleicacid by first saponifying a castor oil by adding a base, e.g. sodiumhydroxide, to the castor oil, acidulating the saponified castor oil togenerate free fatty acids, and then separating or isolating ricinoleicacid from the generated free fatty acids.

FIG. 1 shows an exemplary embodiment of the process (100) for generatingfree fatty acids and optionally fatty acid alkyl esters from asoapstock. A soapstock comprising soaps and unsaponified lipids (101) isfirst combined with a strong base, e.g. sodium hydroxide (102). Theresulting combination is subjected to a saponification reaction (103)wherein substantially ail of the saponifiable material in the soapstock(101) is converted to soaps (104), glycerol (105) and other products.Glycerol (105) is then separated from the soaps (104). The soaps (inwater) (104), are then contacted with CO₂ (106), resulting in theformation of carbonic acid which acidulates the soaps in an acidulationreaction (107) to generate free fatty acids (109) and sodium carbonatesalt (108). The free fatty acids (109) can optionally be combined with asolvent (110), e.g. a solvent comprising an alcohol (111) and anoptional co-solvent (112), and reacted in an esterification reaction(113) at a temperature above the critical temperature of the alcohol anda pressure above the critical pressure of the alcohol to generate fattyacid alkyl esters (114).

Alternative embodiments of the methods and processes are described ingreater detail bellow.

Soapstock Saponification:

In alternative embodiments, the first stage of the process is asaponification reaction with a mixed lipid feedstock. In alternativeembodiments, a mixed lipid feedstock, e.g. a soapstock washwatercomprising water, soaps as well as saponifiable material e.g. glycerides(e.g. mono- di- or triglycerides or any combination thereof) andphospholipids, is mixed with a base, e.g. a strong base such as sodiumhydroxide or potassium hydroxide, and water to generate a saponificationreaction mixture. The generated saponification reaction mixture is thenallowed to react to convert substantially all of the saponifiablematerial in the mixed lipid feedstocks to soaps. During thesaponification reaction, the base serves to cleave substantially all ofthe ester bonds of the saponifiable lipids present in the mixed lipidfeedstock and the cation (e.g. sodium or potassium) joins the fatty acidmolecule to form a salt of a fatty acid (soap) The resulting productcomprises soaps as well as water-soluble material e.g. glycerol.

The following is a reaction scheme showing the saponification of aglyceride molecule in the mixed lipid feedstock in an exemplaryembodiment of the present invention.

The following is a reaction scheme showing the saponification of aphospholipid molecule in the mixed lipid feedstock in an exemplaryembodiment of the present invention.

In alternative embodiments, the saponification reaction is carried outat a temperature in the range of between about room temperature (i.e.about 25° C.) to about 200° C., e.g. between about 50° C. to about 180°C., about 60° C. to about 160° C., about 70° C. to about 140° C., about80° C. to about 120° C., or about 100° C. In alternative embodiments,the saponification reaction is carried out at a pressure of betweenabout 0 to 100 psig, e.g. between about 5 and 50 psig, or between about10 psig and 20 psig. In alternative embodiments, the saponificationreaction is carried out at ambient pressure. In alternative embodiments,the amount of base in the saponification reaction mixture is betweenabout 50 to 150% by weight of the dry weight of the mixed lipidfeedstock (wt/wt %), e.g. about 100 wt/wt % of the dry weight of themixed lipid feedstock.

In alternative embodiments, the base used in the saponification reactionis any base of hydroxide, e.g. sodium hydroxide (NaOH) or potassiumhydroxide (KOH). In alternative embodiments, the amount of base in thesaponification reaction mixture is sufficient to increase the pH of thereaction mixture to a level that is sufficient to saponify substantiallyall of the saponifiable material in the mixed lipid feedstock, e.g. asufficient amount of base to increase the pH of the saponificationreaction mixture to a level greater than a pH of 10, e.g. a pH of 12. Inalternative embodiments, the amount of water in the saponificationreaction is between about 5:1 water-to-feedstock to about 10:1, e.g.about 6:1.

The saponification reaction can take place in any suitable reactionvessel known in the art. In alternative embodiments, the reaction can bea batch or continuous process, depending on the desired throughput ofmaterial from the reaction.

In alternative embodiments, the reaction products generated by thesaponification reaction comprise soaps (salts of fatty acids), glycerol,phosphate salts as well as unsaponifable material e.g. waxes andsterols. In alternative embodiments, the product generated from thesaponification reaction is an emulsification. The product mixturegenerated in the foregoing saponification reaction is referred to hereinas the “saponification product mixture.”

In certain embodiments, following the saponification reaction, theresulting reaction products (i.e. the saponification product mixture)are subjected to a separation step in which the soaps are separated fromthe reaming reaction products, e.g. glycerol. The separation step can beany suitable separation technique known in the art, e.g. filtration,centrifugation, water washing, or any combination of separationtechniques. In an exemplary embodiment, the reaction products from thesaponification step are allowed to settle and then the soaps are skimmedfrom the surface of the mixture. In alternative embodiments, the skimmedsoaps are then subjected to a water wash in which substantially all ofthe non-soap material is removed from the soaps.

In other embodiments, the reaction product generated following thesaponification product is an emulsion comprising, for example, soaps,water and unsaponifiable material e.g. waxes and sterols. In alternativeembodiments, the emulsified saponification reaction product is notsubjected to a subsequent separation step to separate the soaps from theother components of the reaction product. In certain embodiments, theacidulation reaction (described below) is carried out on thesaponification reaction product in the same reaction vessel, without thesaponification reaction product being subjected to a separation step ormoved to a separate reaction vessel for the acidulation step of theprocess. In alternative embodiments, the reaction product generatedduring the saponification step of the process comprises between about30% to about 90% water, e.g. between about 40% to about 70% water, orbetween about 50% to about 60% water.

Acidulation of Soaps:

In alternative embodiments, the soaps, or the reaction product generatedduring the saponification step of the process (i.e. the saponificationproduct mixture), is subjected to an acidulation step in whichsubstantially all of the soaps are acidulated to generate free fattyacids. The soaps are acidulated by mixing them, in any suitable reactionvessel, e.g. the same reaction vessel that was used in thesaponification step, with an acid to form an acidulation reactionmixture. In alternative embodiments, the acid is an organic acid e.g.carbonic acid. In alternative embodiments, carbonic acid is generated bymixing CO₂, e.g. gaseous CO₂, with the saponification reaction product,wherein the CO₂ reacts with the water (present in the saponificationreaction product) to form carbonic acid. In an exemplary embodiment,gaseous CO₂ is then piped or otherwise directed into the reaction vesselwherein the CO₂ reacts with the water present in the saponificationreaction product to form carbonic acid. Once formed, the carbonic acidreacts with the soaps, thereby acidulating them and generating freefatty acids and a corresponding salt. e.g. sodium bicarbonate if sodiumhydroxide (NaOH) was used as the base in the saponification step.

The amount of gaseous CO₂ used in the acidulation step of alternativeembodiments of the process can vary depending on, for example, ambienttemperature and pressure conditions, but is generally sufficient toincrease the pressure of the reaction vessel in which the acidulationreaction is being carried out to between about 0 and about 800 psig,e.g. between about 10 and 700 psig, about 20 to about 600 psig, about 30to about 500 psig, about 40 to about 400 psig, about 50 to about 300psig, about 60 to about 200 psig, about 60 to about 150 psig, about 70to about 140 psig, about 80 to about 120 psig, about 90 to about 110psig, or about 100 psig. In alternative embodiments, the acidulationreaction is carried out at a temperature in the range of between about5° C. to about 120° C., e.g. about 10° C. to about 90° C., about 15° C.to about 70° C., about 20° C. to about 60° C., or about 25° C. to about40° C.

In alternative embodiments, the source of the gaseous CO₂ used in theacidulation step is a “stack gas” or “flue gas” (used interchangeablyherein and referred to as “slack gas”) other source of gaseous CO₂emitted from an industrial process or any oven, furnace, boiler, steamgenerator or the like, e.g. from a coal fired power plant or any otherindustrial process wherein a gaseous waste stream comprising CO₂ isemitted. In alternative embodiments, the stack gas is piped or otherwisetransferred from the emission source to the vessel in which theacidulation reaction is carried out. In alternative embodiments, thestack gas can comprise gaseous CO₂ and possibly other products dependingon the filtration or other purification steps that the stack gas wassubjected to prior to being transferred to the acidulation reactor. Theexact composition of the stack gas will varying depending on theemission source and post-combustion processing steps but is generallycomprised primarily of CO₂ (e.g. about 60% or more CO₂), nitrogenousproducts (e.g. N₂O and NO₂), sulfur dioxide (SO₂), hydrogen sulfide(H₂S), water vapor and possibly other products.

In alternative embodiments wherein a stack gas is used as the CO₂source, other products in the stack gas, e.g. N₂O, NO₂, SO₂, H₂S or thelike can react with the water in the acidulation reaction mixture toform their equivalent aqueous acid species (e.g., SO₂ would react withthe water to generate sulfuric acid). The generation of additional acidproducts in the reaction mixture can serve to increase the reactionefficiency and reduce the total amount of time required to perform theacidulation reaction. As such, the use of a stack gas “waste stream” maybe beneficial in the process, representing an opportunity to utilize awaste stream from one industrial process to benefit another industrialprocess (which might otherwise require expensive processing steps priorto being emitted) as an input for the present process. The processtherefore is a means of diverting what would otherwise be anenvironmental pollutant to an input stream of a separate industrialprocess.

Other products may optionally be added to the acidulation reactionmixture e.g., organic or inorganic acids, e.g. formic acid or sodiumbisulfate. The addition of additional acids can be useful in tailoringthe ash profile of the resulting acidulation product mixture (themixture of products resulting from the acidulation reaction) such thatcertain end products can be used as. e.g. a fertilizer. The optionaladdition of additional acids can serve to increase the reactionefficiency by acidulating soaps that were not acidulated by the carbonicacid.

In alternative embodiments, the desired pH of the acidulation reactionmixture is less than 5, e.g. 2 or 3. In alternative embodiments, theamount of CO₂ and optional other acids (e.g. from stack gas) added tothe acidulation reaction mixture is sufficient to reduce the pH of themixture to below 5 or about 2 or 3.

In alternative embodiments, flowing the addition of the CO₂ (or stackgas, or carbonated water) and optional other acids to the saponificationreaction product and after the reaction vessel has reached the desiredtemperature and pressure to carry out the acidulation step, theresulting reaction mixture is agitated, or otherwise mixed in order tomaximize the contacting of the soaps with the carbonic acid (generatedonce CO₂ reacts with the water present in the saponification reactionmixture). The mixture can be agitated using any suitable method known inthe art, e.g. a spinning blade mixer. In alternative embodiments, themixture is agitated for between about 10 minutes to about 60 minutes,e.g. between about 15 minutes to about 45 minutes, or between about 20minutes to about 25 minutes, or about 30 minutes.

In alternative embodiments, following the agitation step, the contentsof the acidulation reaction vessel are allowed to settle, allowing forthe formation of a lipid layer and aqueous layer. The lipid layer floatson the top of the aqueous layer. In alternative embodiments, the lipidlayer comprises free fatty acids and any non-acidulated soaps, and theaqueous layer comprises, for example, water, glycerol, phosphate salts,e.g. sodium phosphate if sodium hydroxide was the base used in thesaponification step, sodium bicarbonate smaller amounts of sodiumcarbonate (or other equivalent salts if NaOH was not the base used inthe saponification reaction), unsaponifiable material e.g. waxes andsterols, and dissolved carbonic acid. In alternative embodiments, thelipid layer comprising the free fatty acids generated in the acidulationreaction is separated from the remaining reaction products. Theseparation technique used can be any suitable separation technique knownin the art. In alternative embodiments, the reaction products of theacidulation step are transferred to a separation vessel, e.g. a decanterwherein the mixture is allowed to settle and allowed to separate,forming an aqueous phase and a “lipid” phase comprising the free fattyacids which floats on top of the aqueous phase. In alternativeembodiments, the decantation procedure results in the formation ofseparate lipid and aqueous phases in approximately 1 hour or less,depending on the configuration of the reaction vessel. Other separationtechniques, e.g. centrifugation, may also be used in accordance with thepresent invention. In certain embodiments, the acidulation productmixture is not transferred to a separate vessel in order to separate thelipids from the remaining reaction products. In such embodiments, theaqueous layer is drained from the bottom of the reaction vessel and thelipid layer is recovered as the reaction product.

In alternative embodiments, the reaction products generated during theacidulation reaction are transferred to the separation unit in such away that the loss of any gaseous CO₂ is minimized, e.g. via the use of aliquid level control feedback or other suitable method. In certainembodiments, after the acidulation reaction, the reaction vessel isdepressurized, allowing for the dissolved carbonic acid to separate outof the solution as gaseous CO₂. In such embodiments, the captured CO₂ isrecycled for use in the acidulation step.

In alternative embodiments, the process comprises multiple acidulationreactions. In such embodiments, following the first acidulation reactionas described above, the reaction vessel is depressurized and the gaseousCO₂ is captured and recycled. The lipid layer is then separated orotherwise removed from the aqueous layer, and water is added into thereaction vessel containing the lipid layer. Gaseous CO₂ is then added tothe reaction vessel until the desired pressure is reached as describedabove. The reaction vessel is then heated and agitated as previouslydescribed and allowed to settle. The resulting lipid layer is thenseparated or otherwise removed from the aqueous layer as previouslydescribed. The resulting lipid layer is then separated or otherwiseremoved and can optionally be subjected to additional acidulationreactions as previously described, wherein additional water and CO₂ isadded and the resulting mixture agitated at the desired temperature andpressure and the resulting lipid layer is separated or otherwise removedfrom the aqueous layer. The number of acidulation reactions in theprocess can vary depending on the desired free fatty acid yield andprocess economics. In certain embodiments, the number of acidulationreactions is sufficient to acidulate substantially all of the soapspresent in the saponification product mixture, e.g. 3-8 acidulationreactions, e.g. 6 acidulation reactions.

In alternative embodiments, a salt, e.g. sodium chloride or otherequivalent salt, is added to the product mixture following anacidulation reaction. The addition of NaCl or equivalent salt to theacidulation reaction product increases the ionic strength of the productmixture and prevents the lipid layer from emulsifying with the aqueouslayer. In certain embodiments, the process comprises two or moreacidulation reactions and the salt, e.g. NaCl, is added to the productmixture generated by the second acidulation reaction. In certainembodiments, the process comprises three or more acidulation reactions,e.g. six acidulation reactions, and the salt is added to the productmixture generated by the third acidulation reaction.

The acidulation reaction, or multiple acidulation reactions, can takeplace in any suitable reaction vessel known in the art. In alternativeembodiments, the reaction can be a batch or continuous process,depending on the desired throughput of material from the reaction. Inembodiments of the process comprising multiple acidulation reactions,the multiple acidulation reaction can take place in the same reactionvessel or in separate reaction vessels. In embodiments comprisingmultiple acidulation reactions taking place in multiple reactionvessels, the lipid layer generated during each acidulation reaction isseparated or otherwise removed from the corresponding aqueous layer andtransferred to a separate reaction vessel wherein the lipid layer ismixed with water and CO₂ and the resulting mixture is agitated for thedesired period under the desired temperature and pressure conditions andallowed to settle in order to generate a new lipid layer.

In alternative embodiments, the separated free fatty acids generated inthe acidulation reaction are subjected to further processing steps. Inalternative embodiments, the free fatty acids are further separated bytheir carbon chain length, i.e. the number of carbon atoms contained inthe aliphatic tail portion of the free fatty acid, which can comprise,in alternative embodiments, between 4 and 28 carbon atoms. Inalternative embodiments, the free fatty acids are separated by theirsaturation. In alternative embodiments, the saturated free fatty acidsare separated from the unsaturated free fatty acids. In alternativeembodiments, the separated free fatty acids are separated intoshort-chain fatty acids (aliphatic tail length of fewer than 6 carbonatoms), medium-chain fatty acids (aliphatic tail lengths of between 6and 12 carbon atoms), long-chain fatty acids (aliphatic tail length ofbetween 13 and 21 carbon atoms), and very long-chain fatty acids(aliphatic tail length of 22 or more carbon atoms). In alternativeembodiments, the separated free fatty acids are separated intoindividual fatty acids streams based on the length (number of carbonatoms) of their aliphatic tails.

In alternative embodiments, the separated free fatty acids can befurther separated into distinct cuts, based on their aliphatic taillength and/or saturation, using any suitable technique known in the art,e.g. ion exchange, continuous ion exchange, chromatography, continuouschromatography or the like.

Electrolysis of Lipid Phase from Acidulation Reaction:

In alternative embodiments, the lipid phase having been separated in theforegoing acidulation reactions comprises a small percentage ofunreacted soaps, i.e. soaps that were not acidulated to generate freefatty acids, e.g. between about 5 wt % and 20 wt %, or about 10 wt % ofthe lipid phase. In order to increase the overall efficiency of theprocess, alternative embodiments of the process comprise an electrolysisstep wherein the lipid phase comprising a small amount of unreactedsoaps is transferred to an electrolysis unit wherein the soaps in thelipid are reacted with an anolyte to generate free fatty acids. Inalternative embodiments, the addition of the electrolysis step convertssubstantially all, e.g. 95% or more of the unreacted soaps to free fattyacids.

In alternative embodiments comprising the electrolysis step, the lipidlayer from the acidulation reaction(s) is transferred to an electrolysisunit (e.g., a hydrogen evolving cathode (HEC) electrolysis unit)comprising a vessel or suitable container comprising an anode (the anodevessel) and a vessel or other suitable container comprising a cathode(the cathode vessel) separated by a selective filtration membrane, e.g.a polytetrafluoroethylene (PTFE) membrane. In alternative embodiments,the anode is comprised of a mixed metal oxide (MMO) layer coated onto astable metal substrate, e.g. titanium. In alternative embodiments, thecathode can be, for example, titanium or a Monel alloy, or any othersubstrate that is stable in a reducing environment.

In alternative embodiments, a solution comprising an anolyte is added tothe anode vessel. In alternative embodiments the anolyte is a sodiumsalt, e.g. sodium sulfate (for illustrative purposes, sodium sulfate isthe anolyte in the remaining description of the electrolysis step,although those skilled in the art would appreciate that an equivalentanlolyte may be substituted in the process). Simultaneously, the cathodevessel is filled with a catholyte, e.g. sodium hydroxide. In alternativeembodiments, a current is passed through the electrolysis unit resultingin the oxidation of the sodium sulfate, thereby generating sodium ionsand sodium bisulfate. The current also serves to oxidize the water,generating hydrogen ions. The generated sodium ions are pushed acrossthe electrolysis membrane and the generated sodium bisulfate results ina reduction of the pH of the anolyte solution to, e.g. about 3. Once thepH has reached a suitable level, e.g. about 3, a portion of theseparated lipid from the acidulation step is introduced into the vesselwith the anolyte solution wherein any unreacted soaps in the lipid layerreact with the sodium bisulfate to generate free fatty acids and sodiumsulfate. The generated free fatty acids are separated from the anodevessel by any suitable method in the art, e.g. through a pipe at the topof the anode vessel and into separate side tank. The generated sodiumsulfate acts as the regenerated anolyte which, after the fatty acidshave been removed from the anode vessel, is oxidized by passing acurrent through the anode. As such, the electrolysis unit operates in asemi-continuous fashion, wherein sodium sulfate is oxidized to generatesodium bisulfate, thereby lowering the pH of the anolyte solution. Oncethe pH has reached a suitable level, e.g. about 3 additional lipidmaterial from the acidulation reaction step is added, and the soapspresent in the lipid material react with the sodium bisulfate togenerate free fatty acids and sodium sulfate. As the electrical currentis passed through the cathode, the water is reduced, thereby generatinghydroxide ions. As the sodium ions are pushed across the membrane fromthe anode vessel into the cathode vessel, they react with the generatedhydroxide ions to generate sodium hydroxide. In alternative embodiments,the starting concentration of the catholyte (sodium hydroxide) is about30 wt %. As additional sodium hydroxide is generated (from the sodiumions moving across the membrane and into the cathode and reacting withthe hydroxide ions), the concentration of sodium hydroxide increase to,e.g. about 33 wt % before some of the sodium hydroxide is removed tobring the concentration back down to its original concentration, e.g. 30wt %. The generated sodium hydroxide solution comprising sodiumhydroxide and water can be recycled for use in the saponificationreaction, resulting in a more “closed loop” system.

In alternative embodiments, the electrolysis unit is a hydrogen evolvingcathode (HEC) unit with a current density in the range of about 1-10kA/m². In alternative embodiments, the voltage of the individual cellsof the unit can be in the range of between about 3 and 15 volts. Inalternative embodiments, the unit comprises holding tanks for theanolyte and catholyte for electrolyte balancing as the process iscarried out. In alternative embodiments, the holding tank of thecatholyte also serves as the additional tank for the lipid product, aswell as a decanter for separating fatty acids generated in the process.In alternative embodiments, upon startup of the electrolysis unit, thesodium sulfate anolyte is electrolyzed, causing the pH of the anolytesolution to drop from, e.g. about 7 to about 3 to 3.5 and thetemperature of the anode vessel is increased to between about 40-90° C.,or above the melting point of the lipid solution entering the anode. Inalternative embodiments, the lipid product is added to the anolytesolution until the pH increases to, e.g. about 4.5, after which pointthe addition of the lipid product is halted. In alternative embodiments,once the anolyte is electrolyzed, it contacts the soaps, which floats inthe holding tank/decanter due to limited solubility in the anolyte. Oncethe pH in the anolyste solution is reduced to 3-3.5, the circulatingpump halts and fatty acid is decanted from the anolyte for downstreamprocessing.

In alternative embodiments, the foregoing electrolysis procedure is usedas a total replacement of the acidulation reaction comprisingacidulating soaps using carbonic acid. In such embodiments, thesaponification product mixture generated in the saponification reactionis subjected to electrolysis as described above, wherein the productentering the anode vessel of the electrolysis unit is the saponificationproduct mixture rather than the lipid layer separated from theacidulation product mixture.

Treatment of Aqueous Phase from Acidulation Reaction:

Evaporation/Drying

In alternative embodiments, the aqueous phase(s) generated in the one ormore acidulation reactions is subjected to one or more processing stepsin order to recover desirable reaction products that remain in theaqueous phase of the acidulation reaction products and/or to treat theaqueous phase such that the resulting product meets or exceeds relevantregulatory standards relating to animal feed additives.

In alternative embodiments, the aqueous phase, or multiple aqueousphases (i.e. collected from acidulation reactions) is treated to removewater, e.g. by any suitable diving method (e.g. evaporation via fallingfilm, forced recirculation flashing, or any other suitable method) knownin the art, thereby generating a product comprising sodium biconrbonate.Care must be taken so as not to convert sodium bicarbonate to sodiumcarbonate via thermal degradation, so evaporation temperature should beconducted below about 60° C. and should be conducted under a vacuum.

In alternative embodiments, once a majority of the water has beenremoved from the aqueous stream(s), the resulting product can be driedfurther to generate a sodium bicarbonate product that is substantiallyfree of any water, e.g. less than about 20% water or less than about 10%water. Suitable apparatuses for creating a substantially dry sodiumbicarbonate product include fluidized bed dryers, lyophilizers, spraydryers, and rotary drum dryers. The generated dried sodium bicarbonateproduct can be used in any application that utilizes a crude sodiumbicarbonate stream, e.g. as an animal feed additive.

Filtration

In alternative embodiments, the aqueous phase(s) generated in the one ormore acidulation reactions is subjected to one or more processing stepsin order to recover desirable reaction products that remain in theaqueous phase of the acidulation reaction products and/or to treat theaqueous phase such that the resulting product meets or exceeds relevantregulatory standards relating to wastewater. In alternative embodiments,the aqueous phase(s) generated during the one or more acidulationreactions can comprise various organic molecules and salts in additionto water. The exact composition of the aqueous phase(s) will varydepending on the feedstock used in the process, as well as other processvariables, e.g. the reaction conditions, separation technique toseparate the lipid phase from the aqueous phase during the acidulationprocess, etc. In alternative embodiments, the aqueous phase(s) mayinclude, in addition to water: sodium bicarbonate (or equivalent salt ifa base other than sodium hydroxide was used in the saponification step),glycerol, phosphates, cholines, ethanol amines, sodium sulfate (orequivalent salt), inositol, unreacted saponifiable material, e.g. soapsand/or glycerides, residual (small amounts of) free fatty acids, otherorganic or inorganic compounds, or any combination thereof.

The composition of an exemplary aqueous phase generated in theacidulation step comprising 6 acidulation reactions, wherein thefeedstock of the process is a soapstock obtained from the processing ofa crude soybean oil, is described below:

water 92.8% sodium sulfate 1.4% glycerin 0.79% choline 0.06%ethanolamine 0.02% inositol 0.05% phosphate 0.12% sodium bicarbonate4.72%

In alternative embodiments, rite aqueous phase(s) may be treated usingfiltration, e.g. a size-exclusion filtration system. In alternativeembodiments, the filtration step may be operationally in-line (i.e.continuously) with the acidulation step such that aqueous phasegenerated in each acidulation reaction (if the embodiment comprises morethan one acidulation reaction) is treated immediately after or duringthe point at which the aqueous phase is separated from the lipid phase.In other embodiments, the aqueous phases may be collected and treated ina single batch.

In alternative embodiments, wherein the process comprises multipleacidulation reactions, the aqueous phase generated in each of theacidulation reactions is continuously pumped through a filtrationmechanism, e.g. a nano- or microfiltration system or other appropriatemembrane filtration system which may be selected from any of the knownnano-, micro- or other appropriate size-exclusion filtration mechanismsor systems known in the art. In alternative embodiments, the size of thepores of the filter allows for the rejection (i.e. allows the particlesto pass through the membrane) of certain particles, e.g. soaps and/orphosphates, and retains (i.e. does not allow the particles to passthrough the membrane) the sodium bicarbonate (or other equivalent saltif sodium hydroxide was not the salt used in the saponification reactionstep). In alternative embodiments, the particles that pass through themembrane of the filter have a molecular weight less than the molecularweight of sodium palmitate, e.g. sodium bicarbonate, sodium phosphates,etc. In alternative embodiments, rejected particles are sodium (or otherequivalent) soaps, e.g. sodium palmitate, sodium pleate, etc. Inalternative embodiments, the filtration system provides for a moreefficient process in that the soaps and/or other saponifiable materialrejected by the membrane of the filter are returned to the lipid phasefor subsequent acidulation reactions, thereby increasing the overallfatty acid yield of the process.

In alternative embodiments, the addition of a filtration step in theprocess serves to drive the acidulation reaction to completion beremoving the sodium bicarbonate (or other equivalent salt) from theacidulation product Sodium bicarbonate can “back-react” with the fattyacids generated in the acidulation step, wherein some of the fatty acidsreact with the sodium bicarbonate to generate soaps, thereby loweringthe overall fatty acid yield of the process. By removing the generatedsodium bicarbonate from the acidulation products, the opportunity forback-reacting with the sodium bicarbonate is diminished and the fattyacid yield of the process is increased.

In alternative embodiments, the filtration step is carried out in a pHrange of between about 6 and 11 and a pressure of between about 50 and800 psi, while maintaining a temperature of between about 23 and 100° C.In alternative embodiments, the pH of the acidulation product solutionon which the filtration step is carried out varies depending on theamount of sodium bicarbonate in the solution. As the sodium bicarbonateis removed, e.g. via filtration, the pH drops and becomes increasinglyacidic, thereby driving the acidulation reaction to completion. Inalternative embodiments, the aqueous phase of the acidulationreaction(s) is pumped through the filter at a range of between about 1and 100 gallons per minute. In alternative embodiments, the size of thepores in the filter membrane has a molecular weight cutoff (MWCO) ofbetween about 100-250 Daltons.

In alternative embodiments, the retained portion of the aqueous phasecomprising the sodium bicarbonate (or other equivalent salt if sodiumhydroxide was not used in the saponification reaction step) is thensubjected to a concentration step using, for example, reverse osmosis(RO). In alternative embodiments, the conditions for the RO step aresimilar to those of the filtration step, i.e. a pH in the range ofbetween about 6 and 11, a pressure of between about 50 and 800 psi,while maintaining a temperature of between about 23 and 100° C. Inalterative embodiments, the concentrated sodium hydroxide can bediscarded or sold, increasing the overall efficiency of the process. Inalternative embodiments, the water produced in the RO step is suitablepure to be recycled within the acidulation step, thereby increasing theefficiency of the process and reducing total water consumption.

Lime Treatment and Oxidation of Organics

In alternative embodiments, the aqueous phase generated in theacidulation reaction, or multiple acidulation reactions, is collectedand contacted with calcium hydroxide, i.e. slaked lime. The amount oflime added to the aqueous phase is generally an amount sufficient toincrease the pH of the solution to about 11. The lime-treated aqueousphase is allowed to react for a period of between about 1 and 24 hours.During the reaction time, various precipitates form and the pH of thesolution increases to about 12 or 13. In alternative embodiments,wherein sodium hydroxide is the base used in the saponification step, anion-swap occurs between the lime and sodium bicarbonate in the aqueousphase, thereby regenerating the sodium hydroxide for recycling in thesaponification step of the process.

In the same lime-contacting step described above, various calciumprecipitates are formed when they react with various components in theaqueous phase. These precipitates can include, for example, variouscalcium phosphates (i.e. Ca_(x)(PO₄)_(x)). Other components of thelime-treated aqueous phase can include, for example, those products thatwere present in the recovered aquous phase of the one or moreacidulation reactions that did not react with the lime, e.g. glycerol,ethanolamines, choline, other organics, or any combination thereof.

In order to satisfy the Biochemical Oxygen Demand requirements forconventional wastewater treatment facilities, in alternativeembodiments, the lime-treated aqueous phase product may be subjected toan oxidation step in which the organics present in the solution, e.g.phosphorous, glycerin, and other organics are fully oxidized intogaseous products that precipitate out of solution. In alternativeembodiments, the lime-treated aqueous phase is subjected to Fentonoxidation wherein hydrogen peroxide and Fe²⁺ ions are used to catalyzeOH radical formation. In alternative embodiments, the Fenton oxidationstep is carried out by adding between about 1 and 10 grams of hydrogenperoxide per liter of aqueous phase liquid and between about 0.1 and 1.0mol Fe²⁺ per mol of hydrogen peroxide to the lime-treated aqueous phase.The resulting mixture is then allowed to react for between about 1 and24 hours at a temperature of between about 20-50° C. Once the hydrogenperoxide and Fe²⁺ are added to the lime-treated aqueous phase, the pHwill drop rapidly to between about 3 and 9, e.g. less than pH 7. The pHthen rises slowly as the organics are gasified and leave the solution.The reaction is considered complete when the rate of change in the pH ofthe solution is less than about 0.1 units/hour. UV oxidation canoptionally be used in combination with Fenton oxidation.

In alternative embodiments, following the oxidation step, the solutionis then contacted with fresh lime to precipitate any unbound phosphorusand other acidic species. The conditions for the second lime treatmentstep are identical to those of the first lime treatment step.

In alternative embodiments, following the second lime treatment step,the regenerated sodium hydroxide (NaOH) can be concentrated forrecycling and use in the saponification step of the process. The amountof water that must be removed from the solution comprising the NaOH willdepend on the amount of water required for the saponification step.Therefore, if the NaOH is to be recycled in the process, it is notnecessary to remove all of the water from the NaOH. This can be achievedusing any methods known in the art, e.g. evaporation, reverse osmosis,or the like.

Esterification of Free Fatty Acids:

In alternative embodiments, the free fatty acids generated in theacidulation reaction are optionally subjected to an esterification stepin which substantially all of the free fatty acids are esterified toform fatty acid alkyl esters. In alternative embodiments, theesterification is carried out by mixing the free fatty acids with analcohol and subjecting the resulting reaction mixture to a temperatureabove the critical point of the alcohol and a pressure above thecritical pressure of the alcohol, thereby causing the alcohol to becomesupercritical. In its supercritical state, the alcohol reacts with thefree fatty acids to form an ester product of fatty acid alkyl esters.The alcohol used in the esterification step can be an alcohol withbetween 1 and 5 carbons. In alternative embodiments, the alcohol ismethanol or ethanol.

In alternative embodiments, the esterification step comprises a firstemulsification step. The emulsification step can be carried out usingany suitable technique known in the art. In alternative embodiments, theemulsification is carried out by combining the free fatty acids with thealcohol and subjecting the resulting mixture to a high mechanical sheer.The sheer time can be in the range of between about 1 and 100 minutes,or until an emulsification is formed. The molar ratio free fatty acidsto alcohol in the reaction mixture for the esterification step can bebetween about 1:1 to about 1.30, e.g. about 1:10.

In alternative embodiments, after the emulsification is formed, it istransferred to a reaction vessel wherein it is subjected to temperaturesand pressures above the critical point of the alcohol. The reactionvessel can be any suitable reaction vessel capable of withstanding thetemperatures and pressures necessary to allow the alcohol to becomesupercritical. The reaction can be batch or continuous, depending on thedesired throughput. In alternative embodiments, the emulsification ofthe fatty acids and alcohol are pumped into a continuous, plug-flow,continuously stirred tanks, batch-type, or other suitable reactionvessel. In alternative embodiments, the temperature in the reactionvessel is between about 235° C. to about 375° C. and the pressure isbetween about 500-5000 psig. In certain embodiments, the alcohol used inthe esterification step is methanol. In such embodiments, thetemperature in the reaction vessel is above the critical temperature ofmethanol, or above about 240° C., and the pressure in the reactionvessel is above the critical pressure of methanol, or above about 1172psig. In certain embodiments, the alcohol used in the esterificationstep is ethanol. In such embodiments, the temperature in the reactionvessel is above the critical temperature of ethanol, or above about 240°C., and the pressure in the reaction vessel is above the criticalpressure of methanol, or above about 890 psig. The reaction time can bebetween about 10 seconds to about 5 hours, or sufficiently long to allowfor the esterification of substantially all of the free fatty acids,e.g. between about 1 minute and about 4 hours, about 20 minutes andabout 3 hours, about 30 minutes and about 2 hours, or about 40 minutesand about 90 minutes, or about 60 minutes and about 75 minutes.

In alternative embodiments, a co-solvent can optionally be included inthe reaction mixture in the esterification step. The additional of aco-solvent can allow for increased miscibility of the free fatty acidsin the alcohol and can result in decreased reaction times to affectcomplete conversion of free fatty acids to fatty acid alkyl esters. Theco-solvent can be, for example, an organic acid or a hydrocarbon, orcombinations thereof. Suitable hydrocarbon co-solvents include, withoutlimitation, ethane, propane, butane, and hexane, or combinationsthereof. Suitable organic acid co-solvents include, without limitation,formic acid, acetic acid, propionic acid, butyric acid, valeric acid,caprionic acid, oxalic acid, lactic acid, malic acid, citric acid,benzoic acid, carbonic acid, or any combination thereof.

In alternative embodiments, the product mixture following theesterification reaction comprises fatty acid alkyl esters, unreactedalcohol, water, and, if present in the reaction mixture, co-solvent. Ifmethanol was the alcohol used in the esterification reaction, the fattyacid alkyl esters will be fatty acid methyl esters (FAME). If ethanol isused in the esterification reaction, the fatty acid alkyl esters will befatty acid ethyl esters (FAEE).

The reacted material from the esterification reaction (i.e. the productmixture in which the fatty acids are substantially esterified) is passedthrough a high pressure heat exchanger, e.g. a plate, shell and tube,concentric, spiral, or other suitable heat exchanger, wherein heat iswithdrawn from the product mixture and optionally recovered (where theheat can be recycled for use elsewhere in the process, e.g. to heat thereactor used in the esterification step, thereby decreasing the overallenergy requirements of the system).

In alternative embodiments, the heat recovery is conducted underpressure, e.g. at approximately 50 psi below the pressure of the initialreaction, thus, the temperature of the product mixture from which heatis being transferred can be reduced to below the supercritical point ofthe alcohol (e.g. methanol, which has a supercritical point of 240° C.,so the heat is reduced to below 240° C.) while maintaining a pressureabove its critical pressure (e.g. above about 1172 psi), thereby keepingthe solvent, e.g. methanol, in a hot compressed liquid (non-vapor)state. In this alternative embodiment, the product mixture maintains arelatively thin (i.e. non-viscous) consistency, allowing for a high LogMean Temperature Differential and Heat Transfer Coefficient, therebyreducing the total amount of contact area necessary to achieve thedesired heat transfer.

In alternative embodiments, the reactor is heated using an oil, whereoptionally the oil can be heated by burning a natural gas, and the heatcan be recovered by reducing the temperature of the product mixturefrom, for example, 285° C. to 215° C. (using the methanol as the alcoholexample), or equivalent for other solvents, which allows a reduction inthe amount of energy (e.g. natural gas) needed to heat the hearing oilby approximately 30%. In alternative embodiments the heat transferprocess reduces the temperature of the product mixture to, e.g. about215° C. for the methanol as an exemplary alcohol.

In alternative embodiments, the temperature of the reaction mixture isnot lowered to a temperature such that a significant portion of thealcohol, e.g. methanol, remains with the other components of the productmixture during the alcohol, e.g. methanol, recovery step. For example,if the amount of heat recovered resulted in a reduction in temperatureof the product mixture to about 180-190° C., the amount of methanol thatremains with the product mixture following the alcohol (e.g. methanol)recovery step would be in the range of about 10 wt %. By maintaining atemperature of about 215° C., the amount of alcohol (e.g. methanol)remaining in the product mixture following the alcohol (e.g. methanol)recovery step is approximately 2 wt %.

In alternative embodiments, following the heat recovery step, theproduct mixture undergoes a flash process wherein the product mixture istransferred to a flash drum or appropriate or equivalent vessel whereinthe pressure is reduced from the pressure within the heat exchanger,e.g. above 1171 psi or about 1200 psi, to, for example, aboutatmospheric pressure, or about less than 14 psi, e.g. less than 1 psi,or about 0.1 psi. The decrease in pressure results in an environment inwhich the vapor pressure of the alcohol, e.g. methanol, exceeds itsexternal pressure (the pressure of the flash drum or vessel), allowingfor the alcohol, e.g. methanol, water, and, if present, the co-solvent(collectively referred to as the “solvent”) to vaporize or “flash” outof the product mixture.

A flash at 0.1 psi results in approximately 95% of solvent present inthe product mixture to vaporize and leave the flash vessel, withapproximately 5% of the solvent remaining in a liquid state and existingin the bottom of the flash unit along with the remaining products in theproduct mixture (i.e. the “ester stream” comprising the fatty acid alkylesters). In such embodiments, the concentration of solvent (i.e.alcohol, water and, if present, co-solvent) leaving the flash unit in aliquid state (in the ester stream) is approximately 2 wt % of the esterstream.

In alternative embodiments, the ester stream leaves the flash unit at atemperature in the range of between about 110 to about 125° C., e.g.115° C. and is sent to a heat exchanger, e.g. a standard shell and tubeheat exchanger, wherein it is cooled to about 95° C. The recovered heatcan be recycled for use in the process, e.g. to heat the reactor.

In alternative embodiments the solvent (alcohol, water and, if present,co-solvent) mixture that was flashed in a previous step, wherein themixture (if no co-solvent was included in the esterification reaction)is approximately 95 wt % methanol and 5 wt % water, is then distilled toyield a substantially pure alcohol, e.g. methanol product, e.g.approximately 99.8% or more alcohol, e.g. methanol. The substantiallypure alcohol, e.g methanol, product can be recycled for use insubsequent reactions.

In alternative embodiments, the ester stream (i.e. the “bottoms” fromthe previous liquid-vapor separation step comprising primarily fattyacid alkyl esters as well as some small amount of unreacted fatty acidsas well as any of the solvent that was not removed in the previousliquid-vapor separation step) is heated to a temperature in the range ofbetween about 120 to about 250° C., e.g. between about 180 to about 190°C. and transferred to a liquid-vapor separation unit, e.g. a flashchamber, under a vacuum range of between about 5 to about 750 Torr,causing any remaining solvent that was not separated from theesterification product mixture in the previous liquid-vapor separationstep to vaporize and evaporate off of the remaining “bottoms”, i.e. thefatty acid alkyl esters and unreacted fatty acids. The separated solventcan then be purified as described in the previous distillation step toyield a substantially pure alcohol, e.g. methanol product, e.g.,approximately 99.8% or more alcohol, e.g. methanol. The substantiallypure alcohol, e.g. methanol, product can be recycled for use insubsequent reactions.

In alternative embodiments, the ester stream, i.e. the material that didnot evaporate in the previous liquid-vapor separation step, whereinsubstantially all of the solvent has been removed, is then distilled togenerate a product stream comprising substantially purified, i.e.comprising between about 90 and about 99.8 percent fatty acid alkylesters, e.g. 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more, fattyacid alkyl esters, e.g. FAME. In alternative embodiments, the esterstream is purified by transferring the ester stream to a distillationcolumn, e.g. a packed or trayed distillation column, under vacuum ofbetween about 1 to about 200 Torr and heated to a temperature of betweenabout 0 to about 300° C., e.g. about 250° C. The resulting distillatestream is comprised substantially purified, e.g. 99.8% or more, fattyacid alkyl esters. The “bottoms” of the distillation column are thenoptionally transferred to a second distillation column in which thepressure is in the range of about 0.05 to about 100 Torr, causingsubstantially all of the free fatty acids to evaporate. The separatedfree fany acids can optionally be recycled in the process in subsequentesterification reactions.

EXAMPLES Example 1 Saponification and Acidulation of Soapstock

This example describes an exemplary protocol of the invention:

Soybean oil Soapstock Makeup generated was obtained from a natural oilrefining facility and was used as a feedstock to generate free fattyacids (FFAs). The feedstock was first subjected to a saponificationreaction to convert the saponifiable material in the feedstock to soaps.The product resulting from the saponification reaction was thensubjected to an acidulation reaction wherein CO₂ was introduced into thereaction vessel comprising the saponification product. The CO₂ reactedwith the water in the saponification product to form carbonic acid andacidulated soaps, thereby generating an acidulation reaction productcomprising a first lipid layer comprising free fatty acids and a secondaqueous layer comprising water glycerol, sodium bicarbonate,unsaponifiable material, e.g. waxes and sterols, dissolved carbonicacid, and phosphate salts.

Feedstock Description:

The feedstock used in the present example was 55 gallons of soybean oilSoapstock Makeup obtained from a natural oil refinery. The crude soybeanoil was processed using the conventional chemical refining process fortreating crude natural oil. First, phosphoric acid was added to thecrude soybean oil in order make the phospholipids (gums) soluble inwater. Second, the crude soybean oil was treated with sodium hydroxideto neutralize the majority of free fatty acids. During theneutralization process, the free fatty acids reacted with the sodiumhydroxide to form (soaps sodium salts of fatty acids). Water was thenadded to neutralized oil in order to dissolve the soaps and gums and theoil was centrifuged to remove the majority phospholipids (gums) and thesoaps. The oil is then washed with water to remove any excess soap andsodium hydroxide in the oil. The resulting waterwash material isreferred to herein as the Soapstock Makeup, which was the feedstock inthe present example. In addition to soaps and gums, the feedstockcomprised various saponifiable material including mono-, di-, andtriglycerides.

Composition of Feedstock:

55 gallons Soapstock Makeup: 12 wt % Soapstock (Soaps, saponifiablematerial, and unsaponifiable material), and 88 wt % water.

Saponification Reaction:

55 gallons of Soapstock Makeup and 10 lbs of 50 wt % NaOH (referred tocollectively as the “reaction mixture”) were placed in a 75 gallonjacketed (insulated) reaction vessel. The reaction mixture was agitatedusing a spinning blade mixer at 232 rpm. The temperature of the reactionvessel was increased to 100° C. and reacted for 4 hours at atmosphericpressure to allow for complete conversion of substantially allsaponifiable material in the soapstock to soaps. The resulting productmixture was an emulsification comprising soaps, water, andunsaponifiable material.

Acidulation Reaction:

First acidulation reaction: After the saponification reaction, gaseousCO₂ was slowly introduced into the sealed reaction vessel through a portlocated near the bottom of the vessel. CO₂ was continually added to thereaction vessel until the pressure inside the vessel reached 100 psig.The reaction vessel was maintained at a temperature of 95° C. andagitated using a spinning blade mixer spinning at 232 rpms for a periodof 30 minutes. After 30 minutes, the contents of the reaction vesselwere allowed to settle for 10 minutes. During settling, a lipid layerand an aqueous layer formed and the lipid layer floated on top of theaqueous layer. The aqueous layer was drained from the bottom of thereaction vessel. The total weight of the drained aqueous layer was 250lbs.

Second acidulation reaction: After the aqueous layer was removedfollowing the first acidulation reaction, the reaction vessel wasdepressurized to 20 psig. The contents in the reaction vessel wereagitated using the spinning blade mixer as 250 lbs. of tap water wassimultaneously introduced through the top of the reaction vessel. CO₂was continually added to the reaction vessel until the pressure insidethe vessel reached 100 psig. The reaction vessel was maintained at atemperature of 95° C. and agitated using the spinning blade mixer at 232rpms for a period of 30 minutes. After 30 minutes, the contents of thereaction vessel were allowed to settle for 10 minutes. During settling,a lipid layer and an aqueous layer formed and the lipid layer floated ontop of the aqueous layer. The aqueous layer was drained from the bottomof the reaction vessel. The total weight of the drained aqueous layerwas 290 lbs.

Third acidulation reaction: After the brine was removed following thesecond acidulation reaction, the reaction vessel was depressurized to 20psig. The contents in the reaction vessel were agitated using thespinning blade mixer as 290 lbs. of 10 wt % aq. NaCl was simultaneouslyintroduced through the top of the reaction vessel. CO₂ was continuallyadded to the reaction vessel until the pressure inside the vesselreached 100 psig. The reaction vessel was maintained at a temperature of95° C. and agitated using the spinning blade mixer at 232 rpms for aperiod of 30 minutes. After 30 minutes, the contents of the reactionvessel were allowed to settle for 10 minutes. During settling, a lipidlayer and an aqueous layer formed and the lipid layer floated on top ofthe aqueous layer. The aqueous layer was drained from the bottom of thereaction vessel. The total volume of the drained aqueous layer was 20gallons.

The contents of the reaction vessel were allowed to cool to atemperature of 65° C. 20 gallons of hexane was added to the reactionvessel in order to ensure that all lipids in the product mixture wouldseparate from the aqueous layer. CO₂ was continually added to thereaction vessel until the pressure inside the vessel reached 100 psig.The reaction vessel was maintained at a temperature of 65° C. andagitated using the spinning blade mixer at 232 rpms for a period of 30minutes. After 30 minutes, the contents of the reaction vessel wereallowed to settle for 10 minutes. During settling, a hexane layercomprising the lipids (free fatty acids) was formed and floated on topof the product mixture. The reaction vessel was then allowed to drainfrom the bottom until the lipid layer was reached.

Analysis of FFA Content and FFA Profile:

Following the third acidulation reaction, a sample of the hexane layercomprising the free fatty acids (FFAs) was removed from the reactionvessel for analysis. First, the hexane was removed from the sample.Using acid titration, it was determined that the fatty acid content ofthe sample was 79.2 wt % FFA. The remainder of the sample was comprisedof unacidulated soaps and various unsaponifiable material. The fattyacid profile of the sample is shown is Table 2.

TABLE 2 Fatty acid profile of sample C16 C18 C20 18.7% 81.0% 0.3%

Example 2 Conversion of 150 Gallons of Soapstock to Free Fatty Acids

443 lbs of soybean soapstock having a moisture content of 53.7% and atotal fatty acid (TFA) content of 30.3% were added to a 150 gallonInconel 600 batch-type reactor reactor with a three-tier agitator.

Saponification:

It was assumed that the TFA content was ⅓ phospholipid, ⅓ neutral oil,and ⅓ fatty soaps. As such, 56 lbs of 50 wt % NaOH was added to thereaction vessel and allowed to react at 95° C. for 2 hours while beingagitated using a spinning blade agitator unit at 80 rpm. Following thesaponification reaction, several 100-300 g samples of the saponifiedmaterial was taken in triplicate and fully acidulated using sulfuricacid to determine maximum TFA of wet saponified soapstock for use insubsequent mass balance calculations. It was determined that the averagewet TFA content of the saponified soapstock was 19.5%.

Acidulation:

The saponified soapstock material was acidulated in six separateaciduation steps using 300 psig CO₂ and agitated at 80 rpm. Eachacidulation reaction was allowed to progress for 10-30 minutes, afterwhich point 2-3 gallons of saturated sodium sulfate brine was added tothe reaction vessel and agitated for 2 minutes. The mixture was allowedto settle for 10-20 minutes, after which point the aqueous phase wasdrained and the fatty phase was collected. Table 3 summarizes theresults of the acidulation reactions as determined by characteristics ofthe aqueous phases removed after each reaction.

TABLE 3 Summary results of acidulation reactions Reaction Weight ofaqueous Total Dissolved No. pH phase (lbs) Solids (%) 1 8.55 232 25 27.82 363 7 3 7.67 476 3 4 7.11 539 1 5 6.79 596 0.5 6 5.98 537 0.5

Following the sixth acidulation reaction, the fatty phase comprised 3%unreacted soaps. Therefore, 0.5 kg sodium bisulfate was added to thefatty chase to reduce the unreacted soap content to 0%.

Example 3 Electrolysis of Lipid Phase from Acidulation Reaction

Materials: Two one liter working solutions in 2 L glass beakers withstirbars on 1000 W hotplates being recirculated by constant flow rateperistaltic pumps @60° C. (anolyte is saturated aqueous sodium sulfateand catholyte is 10 wt % sodium hydroxide); 5 cm² Nafion 115 membrane,PVC body and tubing, 6″×1″ DSA, 6″×1″ Monel 400 cathode.

Using 0-30 V 0-20 A DC power supply, turn power supply on to provideconstant amperage of 3 A to electrodes in PVC system. Pump anolyte andcatholyte around with their respective peristaltic pumps at 750 mL/minand heat both to 60° C. Reduce anolyte (side with Na₂SO₄ solution) pH toabout 3 to 3.5 before slowly adding enough saponified soapstock toincrease pH of anolyte to 5. Stop addition of saponified soapstock andallow electrochemical cell to reduce anolyte pH back to about 3 to 3.5before adding more saponified soapstock. Halt cycle once 60 minutes ofrun time has been reached and perform liq-liq extraction of floatingfatty material with nonpolar solvent. Rotovap the solvent from crudefatty phase to obtain anhydrous material for characterization.

Result: 12 g fatty material, 1 wt % soap, 99 wt % FFA via titration.

Total energy usage: 1740 kWhr/metric ion FFA produced.

While the forgoing written description of the invention enables one ofordinary skill to make and use what is considered presently to be thebest mode thereof, those of ordinary skill will understand andappreciate the existence of variations, combinations, and equivalents ofthe specific embodiments, methods, and examples herein. The inventionshould therefore not be limited by the above described embodiments,methods and examples, but by all embodiments and methods within thescope and spirit of the invention.

1. A method for generating free fatty acids from a mixed lipidfeedstock, the method comprising: providing the mixed lipid feedstock;combining the mixed lipid feedstock with a base to form a mixture;allowing the mixture to react in a reaction vessel; introducing carbondioxide into the reacted mixture in the reaction vessel to form a firstcarbonic acid within the reaction vessel; mixing the first carbonic acidand the reacted mixture within the reaction vessel; allowing the firstcarbonic acid and reacted mixture to settle within the reaction vessel;and draining a first aqueous layer from the reaction vessel.
 2. Themethod of claim 1, further comprising filtering the first aqueous layerusing a size exclusion filtration system, wherein optionally thefiltering step further comprises a filter having a membrane having aplurality of pores, said pores allowing soaps and phosphates to passthrough said membrane of said filter, and optionally the filtering stepfurther comprises a filter having a membrane, said membrane allowingparticles having a molecular weight less than the molecular weight of asalt, and optionally the filtering step further comprises maintaining apH of the first aqueous layer between about 6 and 11, and optionally thefiltering step further comprises maintaining a pressure of the firstaqueous layer between about 50 and 800 psi, and optionally the filteringstep further comprises maintaining a temperature of the first aqueouslayer between about 23° C. and 100° C. 3-7. (canceled)
 8. The method ofclaim 1, further comprising; (a) an electrolysis step wherein a lipidphase comprising a small amount of unreacted soaps is transferred to anelectrolysis unit wherein the unreacted soaps in the lipid phase arereacted with an anolyte to generate free fatty acids; (b) concentratingthe first aqueous layer from each step, wherein optionally theconcentration step further comprises: (i) maintaining a pH of the firstaqueous layer between about 6 and 11; (ii) maintaining a pressure of thefirst aqueous layer between about 0 and 800 psi: and/or (iii)maintaining a temperature of the first aqueous layer between about 23and 100° C.; (c) combining generated free fatty acids with an alcohol toform a second mixture; and heating and pressurizing the second mixtureto above the critical temperature and pressure of the alcohol, therebyesterifying substantially all of the free fatty acids to generate fattyacid alkyl esters; (d) combining generated free fatty acids with analcohol to form a second mixture; and reacting the second mixture toform a fatty alkyl ester; (e) using a catalyst to cause the reaction ofthe mixed lipid feedstock with the base, wherein optionally the catalystis an acid catalyst; (f) removing generated free fatty acids fromneutral lipids; and reacting the neutral lipids to form a fatty alkylester, and optionally further comprising using a catalyst to cause thereaction, wherein optionally the catalyst is a base catalyst; or (g) anelectrolysis step wherein a lipid phase comprising a small amount ofunreacted soaps is transferred to an electrolysis unit wherein theunreacted soaps in the lipid phase are reacted with an anolyte togenerate free fatty acids. 9-20. (canceled)
 21. The method of claim 1,wherein: (a) the carbon dioxide is introduced as a gaseous flow ofcarbon dioxide into the reaction vessel, or (b) the carbon dioxide isintroduced as a gaseous flow of carbon dioxide into water and the wateris introduced to the reaction vessel.
 22. (canceled)
 23. A method forgenerating free fatty acids from a mixed lipid feedstock, the methodcomprising: providing the mixed lipid feedstock; combining the mixedlipid feedstock with a base to form a mixture; allowing the mixture toreact in a reaction vessel; introducing carbon dioxide into the reactedmixture in the reaction vessel to form a first carbonic acid within thereaction vessel; mixing the first carbonic acid and the reacted mixturewithin the reaction vessel; allowing the first carbonic acid and reactedmixture to settle within the reaction vessel; draining a first aqueouslayer from the reaction vessel; collecting the first aqueous layer; andtreating the collected first aqueous layer with calcium oxides,magnesium oxides, barium oxides, or other polyvalent oxides.
 24. Themethod of claim 23, further comprising; (a) oxidizing the treatedcollected first aqueous layer; or (b) an electrolysis step wherein alipid phase comprising a small amount of unreacted soaps is transferredto an electrolysis unit wherein the unreacted soaps in the lipid phaseare reacted with an anolyte to generate free fatty acids.
 26. A methodfor generating free fatty acids from a mixed lipid feedstock, the methodcomprising: providing the mixed lipid feedstock; combining the mixedlipid feedstock with a base to form a first mixture; allowing the firstmixture to react in a reaction vessel; combining the reacted firstmixture with an organic or inorganic acid, thereby acidulating soaps inthe first mixture to generate free fatty acids; draining a first aqueouslayer from the reaction vessel; combining the generated free fatty acidswith an alcohol to form a second mixture; and heating and pressurizingthe second mixture to above the critical temperature and pressure of thealcohol, thereby esterifying substantially all of the free fatty acidsto generate fatty acid alkyl esters.
 27. The method of claim 26 furthercomprising:. (a) an electrolysis step wherein a lipid phase comprising asmall amount of unreacted soaps is transferred to an electrolysis unitwherein the unreacted soaps in the lipid phase are reacted with ananolyte to generate free fatty acids; wherein optionally the organicacid is carbonic acid, and optionally the carbonic acid is generated byadding carbon dioxide to the saponification product mixture, therebycausing the carbon dioxide to react with the water in the saponificationproduct mixture to form a first carbonic acid; (b) introducing carbondioxide into the reacted mixture in the reaction vessel to form a secondcarbonic acid within the reaction vessel; mixing the second carbonicacid and the reacted mixture within the reaction vessel; allowing thesecond carbonic acid and reacted mixture to settle within the reactionvessel; and draining a second aqueous layer from the reaction vessel.31. A method for generating free fatty acids from a mixed lipidfeedstock, the method comprising: a) providing the mixed lipidfeedstock; b) combining the mixed lipid feedstock with a base to form afirst mixture; c) allowing the first mixture to react in a reactionvessel; d) introducing carbon dioxide into the reacted mixture in thereaction vessel to form a first carbonic acid within the reactionvessel; e) mixing the first carbonic acid and the reacted mixture withinthe reaction vessel; f) allowing the first carbonic acid and reactedmixture to settle within the reaction vessel; g) draining a firstaqueous layer from the reaction vessel; h) removing a generated lipidlayer from the reaction vessel; and i) repeating steps a) through h)above up to 8 times using the generated lipid layer from the reactionvessel as the mixed lipid feedstock for step a).
 32. The method of claim31 further comprising adding a salt to the generated lipid layer priorto any of the reactions.
 33. The method of claim 32 wherein the salt issodium chloride.
 34. The method of claim 31 further comprising addingsodium bisulfate to the generated lipid layer produced in any of the oneor more reactions.
 35. A method for generating an animal feed additivefrom a mixed lipid feedstock, the method comprising: providing the mixedlipid feedstock; combining the mixed lipid feedstock with a base to forma mixture; allowing the mixture to react in a reaction vessel;introducing carbon dioxide into the reacted mixture in the reactionvessel to form a first carbonic acid within the reaction vessel; mixingthe first carbonic acid and the reacted mixture within the reactionvessel; allowing the first carbonic acid and reacted mixture to settlewithin the reaction vessel; draining a first aqueous layer from thereaction vessel; and concentrating the first aqueous layer to generate asodium bicarbonate product that is substantially free of any water. 36.The method of claim 35 wherein the concentration step further comprisingusing evaporation, fluidized bed drying, rotary drum drying,lyophilization, spray drying and reverse osmosis.